Reinforced heat source

ABSTRACT

A reinforced heat source (4) for an aerosol-generating article (2), the reinforced heat source comprising: a blind combustible heat source (38) having a length L; and a non-combustible support (40) embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.

The present invention relates to a reinforced heat source for anaerosol-generating article and to an aerosol-generating articlecomprising the reinforced heat source and an aerosol-forming substrate.

A number of aerosol-generating articles in which tobacco material isheated rather than combusted have been proposed in the art. An aim ofsuch ‘heated’ aerosol-generating articles is to reduce known harmfulsmoke constituents of the type produced by the combustion and pyrolyticdegradation of tobacco in conventional cigarettes.

Typically in heated aerosol-generating articles, an aerosol is generatedby the transfer of heat from a heat source, for example, a chemical,electrical or combustible heat source, to a physically separateaerosol-forming substrate, which may be located within, around ordownstream of the heat source.

In one type of heated aerosol-generating article, an aerosol isgenerated by the transfer of heat from a combustible heat source to aphysically separate aerosol-forming substrate that is located downstreamof the combustible heat source. In use, volatile compounds are releasedfrom the aerosol-forming substrate by heat transfer to theaerosol-forming substrate from the combustible heat source and entrainedin air drawn through the aerosol-generating article. As the releasedcompounds cool, they condense to form an aerosol that is inhaled by theuser. Heat may be transferred from the combustible heat source to theaerosol-forming substrate by one or both of forced convection andconduction.

In this type of heated aerosol-generating article, it is known toinclude a heat-conducting element around and at least a rear portion ofthe combustible carbonaceous heat source and at least a front portion ofthe aerosol-forming substrate of the aerosol-generating article in orderto ensure sufficient conductive heat transfer from the combustible heatsource to the aerosol-forming substrate to obtain an acceptable aerosol.For example, WO 2009/022232 A2 discloses a smoking article comprising acombustible carbonaceous heat source with a central airflow channel, anaerosol-forming substrate downstream of the combustible heat source, anda heat-conducting element around and in contact with a rear portion ofthe combustible carbonaceous heat source and an adjacent front portionof the aerosol-forming substrate. In use, heat generated duringcombustion of the combustible carbonaceous heat source is transferred tothe periphery of the front portion of the aerosol-forming substrate byconduction through the abutting downstream end of the combustiblecarbonaceous heat source and the heat-conducting element. In addition,air drawn through the smoking article by the user is heated as it passesthrough the central airflow channel of the combustible carbonaceous heatsource and then heats the aerosol-generating substrate by convection.

The combustion temperature of combustible heat sources for use in heatedaerosol-generating articles should not be so high as to result incombustion or thermal degradation of the aerosol-forming substrateduring use of the aerosol-generating article. However, the combustiontemperature of the combustible heat sources should be sufficiently highto generate enough heat to release sufficient volatile compounds fromthe aerosol-forming substrate to produce an acceptable aerosol,especially during early puffs.

A variety of combustible heat sources for use in heatedaerosol-generating articles are known in the art.

Known combustible heat sources for use in heated aerosol-generatingarticles are often prone to damage prior to and during use thereof. Forexample, known combustible heat sources combustible heat sources for usein heated aerosol-generating articles are often prone to cracking.Damage to a combustible heat source may result in fragmentation of thecombustible heat source during use of a heated aerosol-generatingarticle. This may lead to loss of combustible material from thecombustible heat source during use of the heated aerosol-generatingarticle. In particular, it may lead to ‘fall-off’ or ‘drop-off’ of someor all of the combustible heat source during use of the heatedaerosol-generating article.

Loss of combustible material from a combustible heat source during useof a heated aerosol-generating article may result in less fuel beingavailable for combustion. This may disadvantageously affect the amountof heat transferred from the combustible heat source to theaerosol-forming substrate and may disadvantageously affect the releaseof volatile compounds from the aerosol-forming substrate of the heatedaerosol-generating article.

Loss of combustible material from a combustible heat source during useof a heated aerosol-generating article may disadvantageously create amess and may detrimentally affect the appearance of the heatedaerosol-generating article.

Loss of combustible material from a combustible heat source during useof a heated aerosol-generating article may disadvantageously causesafety issues for a user of the heated aerosol-generating article.

Known combustible heat sources for use in heated aerosol-generatingarticles often do not generate enough heat after ignition thereof toproduce an acceptable aerosol during early puffs. Known combustible heatsources for use in heated aerosol-generating articles are oftendifficult to ignite. Failure to properly ignite a combustible heatsource may lead to an unacceptable aerosol being delivered to a userduring use of the heated aerosol-generating article.

It has been proposed to include oxidizing agents and other additives incombustible heat sources for use in heated aerosol-generating articlesin order to improve the ignition and combustion properties thereof. Forexample, WO 2012/164077 A1 discloses a combustible heat source for asmoking article comprising carbon and at least one ignition aid selectedfrom the group consisting of metal nitrate salts having a thermaldecomposition temperature of less than about 600 degrees Celsius,chlorates, peroxides, thermitic materials, intermetallic materials,magnesium, zirconium, and combinations thereof.

Inclusion of ignition aids may render known combustible heat sources foruse in heated aerosol-generating articles more prone to damage prior toand during use thereof. For example, inclusion of oxidizing agents thatrelease oxygen during ignition and combustion of known combustible heatsources may render known combustible heat sources more prone tofragmentation during use thereof. In such known combustible heatsources, the oxygen generated within the combustible heat source duringignition and combustion thereof tends to expand. The pressure generatedby the expanding oxygen may lead to cracking and fragmentation of thecombustible heat source. This may lead to ‘fall-off’ or ‘drop-off’ ofsome or all of the combustible heat source during use of the heatedaerosol-generating article.

It would be desirable to provide a heat source for use in heatedaerosol-generating articles that exhibits improved mechanical integrityduring use thereof compared to known combustible heat sources.

It would be desirable to provide a heat source for use in heatedaerosol-generating articles that is less prone to fragmentation duringuse thereof than known combustible heat sources.

It would be desirable to provide a heat source for use in heatedaerosol-generating articles that is less prone to ‘fall-off’ or‘drop-off’ during use thereof than known combustible heat sources.

The invention relates to a reinforced heat source for anaerosol-generating article. The reinforced combustible heat source maycomprise a combustible heat source. The combustible heat source may be ablind combustible heat source. The combustible heat source may have alength L. The reinforced heat source may comprise a non-combustiblesupport. The non-combustible support may be embedded in the combustibleheat source. The non-combustible support may protrude outwardly from thecombustible heat source by a distance of less than or equal to 0.1 L.

The invention also relates to an aerosol-generating article. Theaerosol-generating article may comprise a reinforced heat source. Thereinforced combustible heat source may comprise a combustible heatsource. The combustible heat source may be a blind combustible heatsource. The combustible heat source may have a length L. The reinforcedheat source may comprise a non-combustible support. The non-combustiblesupport may be embedded in the combustible heat source. Thenon-combustible support may protrude outwardly from the combustible heatsource by a distance of less than or equal to 0.1 L. Theaerosol-generating article may comprise an aerosol-generating substrate.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe combustible heat source does not protrude outwardly from thecombustible heat source.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe combustible heat source completely surrounds the non-combustiblesupport.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L; and anaerosol-forming substrate.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support does not protrude outwardly from thecombustible heat source; and an aerosol-forming substrate.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe combustible heat source completely surrounds the non-combustiblesupport; and an aerosol-forming substrate.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a blind combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a blind combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support does not protrude outwardly from thecombustible heat source.

According to the invention there is provided a reinforced heat sourcefor an aerosol-generating article, the reinforced heat sourcecomprising: a blind combustible heat source having a length L; and anon-combustible support embedded in the combustible heat source, whereinthe combustible heat source completely surrounds the non-combustiblesupport.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a blind combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L; and anaerosol-forming substrate.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a blind combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe non-combustible support does not protrude outwardly from thecombustible heat source; and an aerosol-forming substrate.

According to the invention there is further provided anaerosol-generating article comprising: a reinforced heat sourcecomprising a blind combustible heat source having a length L and anon-combustible support embedded in the combustible heat source, whereinthe combustible heat source completely surrounds the non-combustiblesupport; and an aerosol-forming substrate.

It has been found that inclusion of a non-combustible support embeddedin the combustible heat source of reinforced heat sources according tothe invention may advantageously improve the mechanical stability of thecombustible heat source of reinforced heat sources according to theinvention during use thereof.

It has been found that inclusion of a non-combustible support embeddedin the combustible heat source of reinforced heat sources according tothe invention may advantageously reduce or prevent fragmentation of thecombustible heat source of reinforced heat sources according to theinvention during use thereof.

It has been found that inclusion of a non-combustible support embeddedin the combustible heat source of reinforced heat sources according tothe invention may advantageously reduce or prevent ‘fall-off’ or‘drop-off’ of the combustible heat source of reinforced heat sourcesaccording to the invention during use thereof.

Without wishing to be bound by theory, it is believed that inclusion ofa non-combustible support embedded in the combustible heat source ofreinforced heat sources according to the invention increases the bondingforces inside the combustible heat source.

Where the combustible heat source comprises an oxidizing agent thatreleases oxygen during ignition and combustion of the combustible heatsource, inclusion of the non-combustible support may advantageouslyincrease the bonding forces inside the combustible heat sufficiently towithstand the pressure generated by expansion of the oxygen.

Inclusion of a non-combustible support embedded in the combustible heatsource of reinforced heat sources according to the invention, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L, mayadvantageously have minimal impact on the ignition and combustion of thecombustible heat source.

Inclusion of a non-combustible support embedded in the combustible heatsource of reinforced heat sources according to the invention, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L, mayadvantageously have minimal impact on the generation of heat by thecombustible heat source during combustion thereof.

Inclusion of a non-combustible support embedded in the combustible heatsource of reinforced heat sources according to the invention, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L, mayadvantageously have minimal impact on heat transfer from the combustibleheat source to the aerosol-forming substrate of aerosol-generatingarticles according to the invention during use thereof.

Inclusion of a non-combustible support embedded in the combustible heatsource of reinforced heat sources according to the invention, whereinthe non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L, mayadvantageously have minimal impact on the external appearance ofreinforced combustible heat sources and aerosol-generating articlesaccording to the invention.

As used herein with reference to the invention, the terms “distal”,“upstream” and “front” and the terms “proximal”, “downstream” and “rear”are used to describe the relative positions of components, or portionsof components, of aerosol-generating articles according to theinvention. Aerosol-generating articles according to the inventioncomprise a proximal end through which, in use, an aerosol exits theaerosol-generating article for delivery to a user. The proximal end ofthe aerosol-generating article may also be referred to as the mouth endof the aerosol-generating article. In use, a user draws on the proximalend of the aerosol-generating article in order to inhale an aerosolgenerated by the aerosol-generating article.

Aerosol-generating articles according to the invention comprise a distalend. The reinforced heat source is located at or proximate to the distalend of the aerosol-generating article. Components, or portions ofcomponents, of aerosol-generating articles according to the inventionmay be described as being upstream or downstream of one another based ontheir relative positions between the proximal end of theaerosol-generating article and the distal end of the aerosol-generatingarticle.

The proximal end of the aerosol-generating article is downstream of thedistal end of the aerosol-generating article. The proximal end of theaerosol-generating article may also be referred to as the downstream endof the aerosol-generating article and the distal end of theaerosol-generating article may also be referred to as upstream end ofthe aerosol-generating article.

The combustible heat source of reinforced heat sources according to theinvention has a front end face and a rear end face. The front end faceof the combustible heat source is at the upstream end of the combustibleheat source. The upstream end of the combustible heat source is the endof the combustible heat source furthest from the proximal end of theaerosol-generating article. The rear end face of the combustible heatsource is at the downstream end of the combustible heat source. Thedownstream end of the combustible heat source is the end of thecombustible heat source closest to the proximal end of theaerosol-generating article.

As used herein with reference to the invention, the term “longitudinal”is used to describe the direction between the upstream end and thedownstream end of the combustible heat source of reinforced heat sourcesaccording to the invention and aerosol-generating articles according tothe invention.

As used herein with reference to the invention, the term “transverse” isused to describe the direction perpendicular to the longitudinaldirection. That is, the direction perpendicular to the direction betweenthe upstream end and the downstream end of the combustible heat sourceof reinforced heat sources according to the invention andaerosol-generating articles according to the invention.

The combustible heat source of reinforced heat sources according to theinvention has a length L.

As used herein with reference to the invention, the term “length” isused to describe the maximum dimension in the longitudinal direction ofthe combustible heat source of reinforced heat sources according to theinvention and aerosol-generating articles according to the invention.

The combustible heat source may have any desired length L.

The combustible heat source may have a length L of between about 5millimetres and about 20 millimetres.

Preferably, the combustible heat source has a length L of between about7 millimetres and about 17 millimetres.

More preferably, the combustible heat source has a length L of betweenabout 7 millimetres and about 15 millimetres.

Most preferably, the combustible heat source has a length L of betweenabout 7 millimetres and about 13 millimetres.

As used herein with reference to the invention, the term “diameter” isused to describe the maximum dimension in the transverse direction ofthe combustible heat source of reinforced heat sources according to theinvention and aerosol-generating articles according to the invention.

The combustible heat source of reinforced heat sources according to theinvention may have any desired diameter.

The combustible heat source may have a diameter of between about 5millimetres and about 15 millimetres.

Preferably, the combustible heat source has a diameter of between about5 millimetres and about 10 millimetres.

More preferably, the combustible heat source has a diameter of betweenabout 7 millimetres and about 8 millimetres.

Preferably, the combustible heat source is substantially cylindrical.

The combustible heat source is a solid combustible heat source.

Preferably, the combustible heat source is a monolithic solidcombustible heat source. That is, a one-piece solid combustible heatsource.

The combustible heat source may have a mass of between about 300milligrams and about 500 milligrams. For example, the combustible heatsource may have a mass of between about 400 milligrams and about 450milligrams.

Preferably, the combustible heat source is a carbonaceous combustibleheat source.

As used herein with reference to the invention, the term “carbonaceous”is used to describe a combustible heat source comprising carbon.

The combustible heat source may comprise at least about 25 percent byweight of carbon.

Unless stated otherwise, percentages by weight of components of thecombustible heat source recited herein are based on the total dry weightof the combustible heat source.

Preferably, the combustible heat source comprises at least about 30percent by weight of carbon.

More preferably, the combustible heat source comprises at least about 35percent by weight of carbon.

The combustible heat source may comprise at least about 40 percent byweight of carbon.

The combustible heat source may comprise less than or equal to about 60percent by weight of carbon.

Preferably, the combustible heat source comprises less than or equal toabout 55 percent by weight of carbon.

More preferably, the combustible heat source comprises less than orequal to about 50 percent by weight of carbon.

The combustible heat source may comprise less than or equal to about 45percent by weight of carbon.

The combustible heat source may comprise between about 25 percent byweight and about 60 percent by weight of carbon, between about 25percent by weight and about 55 percent by weight of carbon, betweenabout 25 percent by weight and about 50 percent by weight of carbon orbetween about 25 percent by weight and about 45 percent by weight ofcarbon.

Preferably, the combustible heat source comprises between about 30percent by weight and about 60 percent by weight of carbon, betweenabout 30 percent by weight and about 55 percent by weight of carbon,between about 30 percent by weight and about 50 percent by weight ofcarbon or between about 30 percent by weight and about 45 percent byweight of carbon.

More preferably, the combustible heat source comprises between about 35percent by weight and about 60 percent by weight of carbon, betweenabout 35 percent by weight and about 55 percent by weight of carbon,between about 35 percent by weight and about 50 percent by weight ofcarbon or between about 35 percent by weight and about 45 percent byweight of carbon.

The combustible heat source may comprise between about 40 percent byweight and about 60 percent by weight of carbon, between about 40percent by weight and about 55 percent by weight of carbon, betweenabout 40 percent by weight and about 50 percent by weight of carbon orbetween about 40 percent by weight and about 45 percent by weight ofcarbon.

The combustible heat source may be formed using one or more suitablecarbon materials. Advantageously, the combustible heat source compriseone or more carbonised materials. Suitable carbon materials are wellknown in the art and include, but are not limited to, carbon powder andcharcoal powder.

Preferably, the combustible heat source comprises an oxidizing agentthat releases oxygen during ignition of the combustible heat source. Thequantity of oxygen released by the oxidizing agent during ignition ofthe combustible heat source may be sufficient to result in thecombustible heat source undergoing a two-stage combustion process.

In an initial first stage the combustible heat source may exhibit a‘boost’ in temperature and in a subsequent second stage the combustibleheat source may undergo sustained combustion at a lower ‘cruising’temperature.

The initial ‘boost’ in temperature of combustible heat source may arisedue to very rapid propagation of heat throughout the entirety of thecombustible heat source upon ignition of a portion thereof. The veryrapid propagation of heat may be the result of a chain reaction in whicha portion of the combustible heat source that is ignited triggers theignition of an adjacent unignited part of the combustible heat source.

In use in aerosol-generating articles according to the invention, therapid increase in temperature of the combustible heat source to the‘boost’ temperature may quickly raise the temperature of theaerosol-forming substrate to a level at which volatile compounds arereleased from the aerosol-forming substrate. This may ensure thataerosol-generating articles according to the invention produce asensorially acceptable aerosol during early puffs. The subsequentdecrease in temperature of the combustible heat source to the ‘cruising’temperature may ensure that the temperature of the aerosol-formingsubstrate does not reach a level at which combustion or thermaldegradation of the aerosol-forming substrate occurs.

Controlling the temperature of the combustible heat source of reinforcedheat sources according to the invention in the manner described abovemay advantageously enable aerosol-generating articles according to theinvention to be provided that not only produce a sensorially acceptableaerosol during early puffs, but in which combustion or thermaldegradation of the aerosol-forming substrate is also substantiallyavoided.

The amount of oxidizing agent that must be included in order to achievethe two-stage process described above will vary depending on thespecific oxidizing agent included in the combustible heat source.

Preferably, the oxidizing agent is an alkaline earth metal peroxide.

More preferably, the oxidizing agent is calcium peroxide.

The combustible heat source may comprise at least about 15 percent byweight of calcium peroxide.

Preferably, the combustible heat source comprises at least about 20percent by weight of calcium peroxide.

More preferably, the combustible heat source comprises at least about 30percent by weight of calcium peroxide.

The combustible heat source may comprise at least about 40 percent byweight of calcium peroxide.

The combustible heat source may comprise less than or equal to about 65percent by weight of calcium peroxide.

Preferably, the combustible heat source comprises less than or equal toabout 60 percent by weight of calcium peroxide.

More preferably, the combustible heat source comprises less than orequal to about 55 percent by weight of calcium peroxide.

The combustible heat source may comprise less than or equal to about 50percent by weight of calcium peroxide.

The combustible heat source may comprise between about 15 percent byweight and about 65 percent by weight of calcium peroxide, between about15 percent by weight and about 60 percent by weight of calcium peroxide,between about 15 percent by weight and about 55 percent by weight ofcalcium peroxide or between about 15 percent by weight and about 50percent by weight of calcium peroxide.

Preferably, the combustible heat source comprises between about 20percent by weight and about 65 percent by weight of calcium peroxide,between about 20 percent by weight and about 60 percent by weight ofcalcium peroxide, between about 20 percent by weight and about 55percent by weight of calcium peroxide or between about 20 percent byweight and about 50 percent by weight of calcium peroxide.

More preferably, the combustible heat source comprises between about 30percent by weight and about 65 percent by weight of calcium peroxide,between about 30 percent by weight and about 60 percent by weight ofcalcium peroxide, between about 30 percent by weight and about 55percent by weight of calcium peroxide or between about 30 percent byweight and about 50 percent by weight of calcium peroxide.

The combustible heat source may comprise between about 40 percent byweight and about 65 percent by weight of calcium peroxide, between about40 percent by weight and about 60 percent by weight of calcium peroxide,between about 40 percent by weight and about 55 percent by weight ofcalcium peroxide or between about 40 percent by weight and about 50percent by weight of calcium peroxide.

The combustible heat source may comprise one or more binding agents.

As used herein with reference to the invention, the term “binding agent”is used to describe a component of the combustible heat source that iscapable of binding other components of the combustible heat sourcetogether.

The combustible heat source may comprise one or more cellulosic bindingagents.

The combustible heat source may comprise one or more non-cellulosicbinding agents.

The combustible heat source may comprise at least about 3 percent byweight of the one or more binding agents.

Preferably, the combustible heat source comprises at least about 4percent by weight of the one or more binding agents.

More preferably, the combustible heat source comprises at least about 5percent by weight of the one or more binding agents.

The combustible heat source may comprise less than or equal to about 20percent by weight of the one or more binding agents.

Preferably, the combustible heat source comprises less than or equal toabout 15 percent by weight of the one or more binding agents.

More preferably, the combustible heat source comprises less than orequal to about 10 percent by weight of the one or more binding agents.

The combustible heat source may comprise between about 3 percent byweight and about 20 percent by weight of the one or more binding agents,between about 3 percent by weight and about 15 percent by weight of theone or more binding agents or between about 3 percent by weight andabout 10 percent by weight of the one or more binding agents.

Preferably, the combustible heat source comprises between about 4percent by weight and about 20 percent by weight of the one or morebinding agents, between about 4 percent by weight and about 15 percentby weight of the one or more binding agents or between about 4 percentby weight and about 10 percent by weight of the one or more bindingagents.

More preferably, the combustible heat source comprises between about 5percent by weight and about 20 percent by weight of the one or morebinding agents, between about 5 percent by weight and about 15 percentby weight of the one or more binding agents or between about 5 percentby weight and about 10 percent by weight of the one or more bindingagents.

The combustible heat source may comprise one or more carboxylate burnsalts.

As used herein with reference to the invention, the term “carboxylateburn salt” is used to describe a salt of a carboxylic acid other thancarbonic acid. That is, as used herein with reference to the invention,the term “carboxylate burn salt” does not include carbonates orbicarbonates.

The one or more carboxylate burn salts may advantageously promotecombustion of the combustible heat source.

The carboxylate burn salt may comprise a monovalent, divalent, ortrivalent cation and a carboxylate anion.

The carboxylate burn salt may comprise a monovalent, divalent, ortrivalent cation and an acetate, citrate or succinate anion.

The carboxylate burn salt may be an alkali metal carboxylate burn salt.For example, the carboxylate burn salt may be a sodium carboxylate burnsalt or a potassium carboxylate burn salt.

The carboxylate burn salt may be an alkali metal acetate, an alkalimetal citrate or an alkali metal succinate.

Most preferably, the carboxylate burn salt is potassium citrate.

The combustible heat source may comprise a single carboxylate burn salt.

The combustible heat source may comprise a combination of two or moredifferent carboxylate burn salts. The two or more different carboxylateburn salts may comprise different carboxylate anions. The two or moredifferent carboxylate burn salts may comprise different cations. Forexample, the combustible heat source may comprise a combination of analkali metal citrate and an alkaline earth metal succinate.

The combustible heat source may comprise at least about 0.1 percent byweight of the one or more carboxylate burn salts.

The combustible heat source may comprise at least about 0.5 percent byweight of the one or more carboxylate burn salts.

Preferably, the combustible heat source comprises at least about 1percent by weight of the one or more carboxylate burn salts.

The combustible heat source may comprise less than or equal to about 4percent by weight of the one or more carboxylate burn salts.

Preferably, the combustible heat source comprises less than or equal toabout 3 percent by weight of the one or more carboxylate burn salts.

The combustible heat source may comprise between about 0.1 percent byweight and about 4 percent by weight of the one or more carboxylate burnsalts or between about 0.1 percent by weight and about 3 percent byweight of the one or more carboxylate burn salts.

The combustible heat source may comprise between about 0.5 percent byweight and about 4 percent by weight of the one or more carboxylate burnsalts or between about 0.5 percent by weight and about 3 percent byweight of the one or more carboxylate burn salts.

Preferably, the combustible heat source comprises between about 1percent by weight and about 4 percent by weight of the one or morecarboxylate burn salts or between about 1 percent by weight and about 3percent by weight of the one or more carboxylate burn salts.

The combustible heat source may be formed by: combining components ofthe combustible heat source to form a mixture; and forming the mixtureinto a desired shape.

For example, the combustible heat source may be formed by: combining oneor more carbon materials, an oxidizing agent, one or more binding agentsand any other components of the combustible heat source to form amixture; and forming the mixture into a desired shape.

The components of the combustible heat source may be combined to form amixture using suitable known methods such as, for example, drygranulation, wet granulation, high shear mixing, spheronization orextrusion.

The mixture may be formed into a desired shape using suitable knownceramic forming methods such as, for example, slip casting, extrusion,injection moulding, die compaction or pressing.

Preferably, the mixture is formed into a desired shape by a pressingprocess.

After formation the desired shape may be dried to reduce the moisturecontent thereof. The desired shape may be dried using suitable knownmethods. For example, the desired shape may be dried in an oven.

The combustible heat source may be a non-blind combustible heat source.

As used herein with reference to the invention, the term “non-blind” isused to describe a combustible heat source including at least oneairflow channel extending along the length of the combustible heatsource through which air may be drawn for inhalation by a user.

Preferably, the combustible heat source is a blind combustible heatsource.

As used herein with reference to the invention, the term “blind” is usedto describe a combustible heat source that does not include any airflowchannels extending along the length of the combustible heat sourcethrough which air may be drawn for inhalation by a user.

The combustible heat source may comprise one or more closed or blockedchannels through which air may not be drawn for inhalation by a user.

For example, the combustible heat source may comprise one or more closedchannels that extend only part way along the length of the combustibleheat source.

The inclusion of one or more closed channels may increase the surfacearea of the combustible heat source that is exposed to oxygen from theair. This may advantageously facilitate ignition and sustainedcombustion of the combustible heat source.

Reinforced combustible heat sources according to the invention comprisea non-combustible support embedded in the combustible heat source.

As used herein with reference to the invention, the term“non-combustible support” is used to describe a support that issubstantially non-combustible at temperatures reached by the combustibleheat source during ignition and combustion thereof.

The non-combustible support may be formed from any suitable material orcombination of materials that are substantially non-combustible attemperatures reached by the combustible heat source during ignition andcombustion thereof.

The non-combustible support may be formed from one or more materialshaving a melting point of greater than or equal to about 1200° C.

Preferably, the non-combustible support is formed from one or morematerials having a melting point of greater than or equal to about 1300°C.

More preferably, the non-combustible support is formed from one or morematerials having a melting point of greater than or equal to about 1400°C.

Preferably, the non-combustible support is formed from one or moremetals, one or more alloys or a combination of one or more metals andone or more alloys.

The non-combustible support may be formed from one or more materialsselected from the group consisting of chromium, iron, nickel and steel.

Preferably, the non-combustible support is formed from steel.

More preferably, the non-combustible support is formed from stainlesssteel.

The non-combustible support protrudes outwardly from the combustibleheat source by a distance of less than or equal to 0.1 L, where L is thelength of the combustible heat source.

The non-combustible support may protrude outwardly from the combustibleheat source by a distance of less than or equal to 0.08 L, less than orequal to 0.06 L, less than or equal to about 0.04 L or less than orequal to about 0.02 L.

Preferably, the non-combustible support does not protrude outwardly fromthe combustible heat source.

The combustible heat source at least partially surrounds thenon-combustible support.

Preferably, the combustible heat source completely surrounds thenon-combustible support. In such embodiments, the non-combustiblesupport is entirely enclosed within the combustible heat source.

Where the combustible heat source completely surrounds thenon-combustible support, the non-combustible support advantageously doesnot affect the external appearance of the combustible heat source.

The non-combustible support may extend a distance of greater than orequal to about 0.3 L in the longitudinal direction within thecombustible heat source.

Preferably, the non-combustible support extends a distance of greaterthan or equal to about 0.4 L within the combustible heat source.

The non-combustible support may extend a distance of greater than orequal to about 0.5 L within the combustible heat source.

The non-combustible support may extend a distance of less than or equalto about 1.0 L within the combustible heat source.

Preferably, the non-combustible support extends a distance of less thanor equal to about 0.9 L within the combustible heat source.

The non-combustible support may extend a distance of less than or equalto about 0.8 L within the combustible heat source.

The non-combustible support may extend a distance of between about 0.3 Land about 1.0 L, between about 0.3 L and about 0.9 L or between about0.3 L and about 0.8 L within the combustible heat source.

Preferably, the non-combustible support extends a distance of betweenabout 0.4 L and about 1.0 L, between about 0.4 L and about 0.9 L orbetween about 0.4 L and about 0.8 L within the combustible heat source.

The non-combustible support may extend a distance of between about 0.5 Land about 1.0 L, between about 0.5 L and about 0.9 L or between about0.5 L and about 0.8 L within the combustible heat source.

The total volume of the one or more non-combustible support elementsrelative to the volume of the combustible heat source may advantageouslybe chosen to improve the mechanical integrity of the combustible heatsource while eliminating or reducing the impact of the non-combustiblesupport on the generation of heat by the combustible heat source duringcombustion thereof.

The non-combustible support may comprise one or more non-combustiblesupport elements.

The one or more combustible support elements may have any suitableshape.

Suitable shapes include, but are not limited to, coils, cones,cup-shapes, cubes, helices, pins, rectangular cuboids, rods, spirals andtubes.

The one or more combustible support elements may have any suitable size.

The one or more non-combustible support elements may have a length ofgreater than or equal to about 0.3 L.

Preferably, the one or more non-combustible support elements have alength of greater than or equal to about 0.4 L.

The one or more non-combustible support elements may have a length ofgreater than or equal to about 0.5 L or greater than or equal to about0.6 L.

The one or more non-combustible support elements may have a length ofless than or equal to about 1.1 L.

The one or more non-combustible support elements may have a length ofless than or equal to about 1.0 L.

Preferably, the one or more non-combustible support elements have alength of less than or equal to about 0.9 L.

The one or more non-combustible support elements may have a length ofless than or equal to about 0.8 L

The one or more non-combustible support elements may have a length ofbetween about 0.3 L and about 1.1 L, between about 0.3 L and about 1.0L, between about 0.3 L and about 1.0 L, between about 0.3 L and about0.9 L or between about 0.3 L and about 0.8 L.

Preferably, the one or more non-combustible support elements have alength of between about 0.4 L and about 1.1 L. More preferably, the oneor more non-combustible support elements have a length of between about0.4 L and about 1.0 L. Most preferably, the one or more non-combustiblesupport elements have a length of between about 0.4 L and about 0.9 L.For example, the one or more non-combustible support elements may have alength of between about 0.4 L and about 0.8 L.

The one or more non-combustible support elements may have a length ofbetween about 0.5 L and about 1.1 L, between about 0.5 L and about 1.0L, between about 0.5 L and about 1.0 L, between about 0.5 L and about0.9 L or between about 0.5 L and about 0.8 L.

The one or more non-combustible support elements may have a length ofbetween about 0.6 L and about 1.1 L, between about 0.6 L and about 1.0L, between about 0.6 L and about 1.0 L, between about 0.6 L and about0.9 L or between about 0.6 L and about 0.8 L.

The total volume of the one or more non-combustible support elementsrelative to the volume of the combustible heat source may advantageouslybe chosen to improve the mechanical integrity of the combustible heatsource while eliminating or reducing the impact of the non-combustiblesupport on the generation of heat by the combustible heat source duringcombustion thereof.

Preferably the total volume of the one or more non-combustible supportelements is greater than or equal to about 0.00005V, where V is thevolume of the combustible heat source.

The total volume of the one or more non-combustible support elements maybe greater than or equal to about 0.0001V.

Preferably the total volume of the one or more non-combustible supportelements is less than or equal to about 0.05V.

The total volume of the one or more non-combustible support elements maybe less than or equal to about 0.025V.

The total volume of the one or more non-combustible support elements maybe between about 0.00005V and about 0.05V or between about 0.00005V andabout 0.025V.

The total volume of the one or more non-combustible support elements maybe between about 0.0001V and about 0.05V or between about 0.0001V andabout 0.025V.

The non-combustible support may comprise a single non-combustiblesupport element.

For example, the non-combustible support may comprise a single elongaterod.

The non-combustible support may comprise a plurality of non-combustiblesupport elements.

For example, the non-combustible support may comprise a plurality ofelongate rods.

Where the non-combustible support comprises one or more elongate rods,the one or more elongate rods may have a diameter of between about 0.001D and about 0.7 D, where D is the diameter of the combustible heatsource.

Preferably the one or more elongate rods have a diameter of betweenabout 0.01 D and about 0.3 D.

The non-combustible support may be formed from a mesh.

The mesh number of the mesh relative to the volume of the combustibleheat source may advantageously be chosen to improve the mechanicalintegrity of the combustible heat source while eliminating or reducingthe impact of the non-combustible support on the generation of heat bythe combustible heat source during combustion thereof.

Where the non-combustible support is formed from a mesh, the mesh mayhave a US mesh size of between 20 and 150.

Preferably, the mesh has a US mesh number of between 50 and 100.

Where the non-combustible support is formed from a mesh, the mesh may beformed from strands or wires having a thickness of have a US mesh numberof between about 20 microns to about 80 microns.

The mesh may be formed into any desired shape.

For example, the non-combustible support may comprise a cylindricalhollow tube formed from a mesh.

The non-combustible support may be embedded in the combustible heatsource during formation of the combustible heat source.

For example, where the combustible heat source is formed by a pressingprocess, the non-combustible support and a mixture of the components ofthe combustible heat source may be placed in a mould and compressedtogether to form the reinforced heat source.

Aerosol-generating articles according to the invention comprise areinforced heat source according to the invention and an aerosol-formingsubstrate.

As used herein with reference to the invention, the term“aerosol-forming substrate” is used to describe a substrate comprisingaerosol-forming material capable of releasing upon heating volatilecompounds, which can form an aerosol. The aerosols generated fromaerosol-forming substrates of aerosol-generating articles according tothe invention may be visible or invisible and may include vapours (forexample, fine particles of substances, which are in a gaseous state,that are ordinarily liquid or solid at room temperature) as well asgases and liquid droplets of condensed vapours.

The aerosol-forming substrate may be in the form of a plug or segmentcomprising a material capable of releasing upon heating volatilecompounds, which can form an aerosol, circumscribed by a wrapper. Wherean aerosol-forming substrate is in the form of such a plug or segment,the entire plug or segment including the wrapper is considered to be theaerosol-forming substrate.

Preferably, the aerosol-forming substrate is downstream of thereinforced heat source. That is, the aerosol-forming substrate ispreferably between the reinforced heat source and the distal end of theaerosol-generating article.

The aerosol-forming substrate may abut the reinforced heat source.

The aerosol-forming substrate may be longitudinally spaced-apart fromthe reinforced heat source.

Advantageously, the non-combustible support embedded in the combustibleheat source of the reinforced heat source does not directly contact theaerosol-forming substrate. The absence of any direct contact between thenon-combustible support and the aerosol-forming substrate mayadvantageously eliminate or reduce the impact of the non-combustiblesupport on heat transfer from the combustible heat source to theaerosol-forming substrate during use of the aerosol-generating article.

Advantageously, the aerosol-forming substrate comprises aerosol-formingmaterial comprising an aerosol-former.

The aerosol former may be any suitable compound or mixture of compoundsthat, in use, facilitates formation of a dense and stable aerosol andthat is substantially resistant to thermal degradation at the operatingtemperature of the aerosol-generating article. Suitable aerosol formersare known in the art and include, but are not limited to: polyhydricalcohols, such as triethylene glycol, propylene glycol, 1,3-butanedioland glycerine; esters of polyhydric alcohols, such as glycerol mono-,di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylicacids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

Advantageously, the aerosol former comprises one or more polyhydricalcohols.

More advantageously, the aerosol former comprises glycerine.

Preferably, the aerosol-forming substrate is a solid aerosol-formingsubstrate. The aerosol-forming substrate may comprise both solid andliquid components.

The aerosol-forming substrate may comprise plant-based material. Theaerosol-forming substrate may comprise homogenised plant-based material.

The aerosol-forming substrate may comprise nicotine.

The aerosol-forming substrate may comprise tobacco material.

As used herein with reference to the invention, the term “tobaccomaterial” is used to describe any material comprising tobacco,including, but not limited to, tobacco leaf, tobacco rib, tobacco stem,tobacco stalk, tobacco dust, expanded tobacco, reconstituted tobaccomaterial and homogenised tobacco material.

The tobacco material may, for example, be in the form of powder,granules, pellets, shreds, strands, strips, sheets or any combinationthereof.

Advantageously, the aerosol-forming substrate comprises homogenisedtobacco material.

As used herein with reference to the invention, the term “homogenisedtobacco material” is used to describe a material formed by agglomeratingparticulate tobacco.

In certain embodiments, the aerosol-forming substrate advantageouslycomprises a plurality of strands of homogenised tobacco material.

Advantageously, the plurality of strands of homogenised tobacco materialmay be aligned substantially parallel to one another within theaerosol-forming substrate.

In certain embodiments, the aerosol-forming substrate advantageouslycomprises a gathered sheet of homogenised tobacco material.

The aerosol-forming substrate may comprise a rod comprising a gatheredsheet of homogenised tobacco material.

As used herein with reference to the aerosol-forming substrate of theinvention, the term “rod” is used to describe a substantiallycylindrical element of substantially circular, oval or ellipticalcross-section.

As used herein with reference to the invention, the term “sheet” is usedto describe a laminar element having a width and length substantiallygreater than the thickness thereof.

As used herein with reference to the invention, the term “gathered” isused to describe a sheet that is convoluted, folded, or otherwisecompressed or constricted substantially transversely to the longitudinalaxis of the aerosol-generating article.

The aerosol-forming substrate may comprise aerosol-forming material anda wrapper around and in contact with the aerosol-forming material.

The wrapper may be formed from any suitable sheet material that iscapable of being wrapped around aerosol-forming material to form anaerosol-forming substrate.

In certain embodiments, the aerosol-forming substrate may comprise a rodcomprising a gathered sheet of homogenised tobacco material and awrapper around and in contact with the tobacco material.

In certain embodiments, the aerosol-forming substrate advantageouslycomprises a gathered textured sheet of homogenised tobacco material.

As used herein with reference to the invention, the term “texturedsheet” is used to describe a sheet that has been crimped, embossed,debossed, perforated or otherwise deformed.

Use of a textured sheet of homogenised tobacco material mayadvantageously facilitate gathering of the sheet of homogenised tobaccomaterial to form the aerosol-forming substrate.

The aerosol-forming substrate may comprise a gathered textured sheet ofhomogenised tobacco material comprising a plurality of spaced-apartindentations, protrusions, perforations or any combination thereof.

The aerosol-forming substrate may comprise a gathered crimped sheet ofhomogenised tobacco material.

As used herein with reference to the invention, the term “crimped sheet”is used to describe a sheet having a plurality of substantially parallelridges or corrugations.

Advantageously, when an aerosol-generating article according to theinvention comprising the aerosol-forming substrate has been assembled,the substantially parallel ridges or corrugations extend along orparallel to the longitudinal axis of the aerosol-generating article.This facilitates gathering of the crimped sheet of homogenised tobaccomaterial to form the aerosol-forming substrate.

However, it will be appreciated that crimped sheets of homogenisedtobacco material for inclusion in aerosol-forming substrates ofaerosol-generating articles according to the invention may alternativelyor in addition have a plurality of substantially parallel ridges orcorrugations that are disposed at an acute or obtuse angle to thelongitudinal axis of the aerosol-generating article when theaerosol-generating article has been assembled.

Preferably, the aerosol-forming substrate is substantially cylindrical.

The aerosol-forming substrate may have a length of between about 5millimetres and about 20 millimetres.

Preferably, the aerosol-forming substrate has a length of between about6 millimetres and about 15 millimetres.

More preferably, the aerosol-forming substrate has a length of betweenabout 7 millimetres and about 12 millimetres.

The aerosol-forming substrate may have a diameter of between about 5millimetres and about 15 millimetres.

Preferably, the aerosol-forming substrate has a diameter of betweenabout 5 millimetres and about 10 millimetres

More preferably, the aerosol-forming substrate has a diameter of betweenabout 7 millimetres and about 8 millimetres.

Where the combustible heat source is a non-blind combustible heatsource, in use air drawn through the aerosol-generating article forinhalation by a user passes through at least one airflow channel alongthe length of the combustible heat source.

Where the combustible heat source is a non-blind combustible heatsource, heating of the aerosol-forming substrate occurs by conductionand forced convection.

Where the combustible heat source is a blind combustible heat source, inuse air drawn through the aerosol-generating article for inhalation by auser does not pass through any airflow channels along the length of theblind combustible heat source.

Where the combustible heat source is a blind combustible heat source,heating of the aerosol-forming substrate occurs primarily by conductionand heating of the aerosol-forming substrate by forced convection isminimised or reduced. Where the combustible heat source is a blindcombustible heat source, it is particularly important to optimise theconductive heat transfer between the combustible heat source and theaerosol-forming substrate.

Where the combustible heat source is a blind combustible heat source,the lack of any airflow channels extending along the length of thecombustible heat source through which air may be drawn for inhalation bya user may advantageously substantially prevent or inhibit activation ofcombustion of the combustible heat source during puffing by a user. Thismay advantageously substantially prevent or inhibit spikes in thetemperature of the aerosol-forming substrate during puffing by a user.

By preventing or inhibiting activation of combustion of the combustibleheat source, and so preventing or inhibiting excess temperatureincreases in the aerosol-forming substrate, combustion or pyrolysis ofthe aerosol-forming substrate under intense puffing regimes may beadvantageously avoided. In addition, the impact of a user's puffingregime on the composition of the mainstream aerosol may beadvantageously minimised or reduced.

Inclusion of a blind combustible heat source may advantageouslysubstantially prevent or inhibit combustion and decomposition productsand other materials formed during ignition and combustion of thecombustible heat source from entering air drawn through theaerosol-generating article for inhalation by a user.

Where the combustible heat source is a blind combustible heat source,aerosol-generating articles according to the invention comprise one ormore air inlets downstream of the combustible heat source for drawingair into the aerosol-generating article for inhalation by a user. Airdrawn through the aerosol-generating article for inhalation by a userenters the aerosol-generating article through the one or more air inletsand not through the distal end of the aerosol-generating article.

Aerosol-generating articles according to the invention may comprise oneor more air inlets around the periphery of the aerosol-formingsubstrate.

In such embodiments, during puffing by a user cool air is drawn into theaerosol-forming substrate of the aerosol-generating article through theone or more air inlets around the periphery of the aerosol-formingsubstrate. This may advantageously reduce the temperature of theaerosol-forming substrate and so substantially prevent or inhibit spikesin the temperature of the aerosol-forming substrate during puffing by auser.

As used herein with reference to the invention, the term “cool air” isused to describe ambient air that is not significantly heated by thecombustible heat source upon puffing by a user.

By preventing or inhibiting spikes in the temperature of theaerosol-forming substrate, the inclusion of one or more air inletsaround the periphery of the aerosol-forming substrate, mayadvantageously help to avoid or reduce combustion or pyrolysis of theaerosol-forming substrate under intense puffing regimes.

Inclusion of one or more air inlets around the periphery of theaerosol-forming substrate may advantageously help to minimise or reducethe impact of a user's puffing regime on the composition of themainstream aerosol of the aerosol-generating article.

In certain preferred embodiments, aerosol-generating articles accordingto the invention may comprise one or more air inlets located proximateto a downstream end of the aerosol-forming substrate.

Aerosol-generating articles according to the invention may comprise oneor more air inlets downstream of the aerosol-forming substrate. That is,one or more air inlets located between the aerosol-forming substrate andthe proximal end of the aerosol-generating article.

Aerosol-generating articles according to the invention may comprise areinforced heat source according to the invention, an aerosol-formingsubstrate and one or more other components.

The combustible heat source, the aerosol-forming substrate and, whereincluded, the one or more other components of the aerosol-generatingarticle may be assembled within one or more wrappers to form an elongaterod having a proximal end and an opposed distal end. Aerosol-generatingarticles according to the invention may thus resemble conventionallit-end cigarettes.

The one or more other components may comprise one or more of a cap, atransfer element or spacer element, an aerosol-cooling element or heatexchanger and a mouthpiece.

Aerosol-generating articles according to the invention may comprise acap configured to at least partially cover a front portion of thereinforced heat source. The cap may be removable to expose the frontportion of the reinforced heat source prior to use of theaerosol-generating article. The cap may advantageously protect thereinforced heat source prior to use of the aerosol-generating article.

As used herein with reference to the invention, the term “cap” is usedto describe a protective cover at the distal end of theaerosol-generating article that substantially surrounds a front portionof the reinforced heat source.

For example, aerosol-generating articles according to the invention maycomprise a removable cap attached at a line of weakness to the distalend of the aerosol-generating article, wherein the cap comprises acylindrical plug of material circumscribed by a wrapper as described inWO 2014/086998 A1.

Aerosol-generating articles according to the invention may comprise oneor more transfer elements or spacer elements.

Aerosol-generating articles according to the invention may comprise atransfer element or spacer element downstream of the aerosol-formingsubstrate. That is, a transfer element or spacer element located betweenthe aerosol-forming substrate and the proximal end of theaerosol-generating article.

The transfer element may abut the aerosol-forming substrate.Alternatively, the transfer element may be longitudinally spaced-apartfrom the aerosol-forming substrate.

The inclusion of a transfer element may advantageously allow cooling ofthe aerosol generated by heat transfer from the combustible heat sourceto the aerosol-forming substrate.

The inclusion of a transfer element may advantageously allow the overalllength of the aerosol-generating article to be adjusted to a desiredvalue through an appropriate choice of the length of the transferelement. For example, the inclusion of a transfer element may allow theoverall length of the aerosol-generating article to be adjusted to alength similar to that of a conventional cigarette.

The transfer element may have a length of between about 7 millimetresand about 50 millimetres. For example, the transfer element may have alength of between about 10 millimetres and about 45 millimetres or alength of between about 15 millimetres and about 30 millimetres.

The transfer element may have other lengths depending upon the desiredoverall length of the aerosol-generating article and the presence andlength of other components within the aerosol-generating article.

The transfer element may comprise an open-ended tubular hollow body. Inuse, air drawn into the aerosol-generating article by a user may passthrough the open-ended tubular hollow body as it passes downstreamthrough the aerosol-generating article from the aerosol-formingsubstrate to the proximal end of the aerosol-generating article.

The open-ended tubular hollow body may be formed from one or morematerials that are substantially thermally stable at the temperature ofthe aerosol generated by the transfer of heat from the combustible heatsource to the aerosol-forming substrate. Suitable materials are known inthe art and include, but are not limited to: paper; cardboard;thermoplastics, such a cellulose acetate; and ceramics.

Aerosol-generating articles according to the invention may comprise anaerosol-cooling element or heat exchanger downstream of theaerosol-forming substrate. That is, an aerosol-cooling element or heatexchanger located between the aerosol-forming substrate and the proximalend of the aerosol-generating article.

The aerosol-cooling element may advantageously cool the aerosolgenerated by heat transfer from the combustible heat source to theaerosol-forming substrate.

The aerosol-cooling element may comprise a plurality of longitudinallyextending channels.

The aerosol-cooling element may comprise a gathered sheet of materialselected from the group consisting of metallic foil, polymeric material,and substantially non-porous paper or cardboard.

The aerosol-cooling element may comprise a gathered sheet of materialselected from the group consisting of polyethylene (PE), polypropylene(PP), polyvinylchloride (PVC), polyethylene terephthalate (PET),polylactic acid (PLA), cellulose acetate (CA), and aluminium foil.

The aerosol-cooling element may comprise a gathered sheet ofbiodegradable polymeric material, such as polylactic acid (PLA) or agrade of Mater-Bi® (a commercially available family of starch basedcopolyesters).

Where aerosol-generating articles according to the invention comprise atransfer element downstream of the aerosol-forming substrate and anaerosol-cooling element downstream of the aerosol-forming substrate, theaerosol-cooling element is preferably downstream of the transferelement. That is, the aerosol-cooling element is preferably locatedbetween the transfer element and the proximal end of theaerosol-generating article.

Aerosol-generating articles according to the invention may comprise amouthpiece downstream of the aerosol-forming substrate. That is, amouthpiece located between the aerosol-aerosol-forming and the proximalend of the aerosol-generating article.

Preferably, aerosol-generating articles according to the inventioncomprise a mouthpiece located at the proximal end of theaerosol-generating article.

The mouthpiece may be of low filtration efficiency or very lowfiltration efficiency.

The mouthpiece may be a single segment mouthpiece.

The mouthpiece may be a multi-segment mouthpiece.

The mouthpiece may comprise one or more segments comprising filtrationmaterial.

Suitable filtration materials are known in the art and include, but arenot limited to, cellulose acetate and paper.

The mouthpiece may comprise one or more segments comprising absorbentmaterial.

The mouthpiece may comprise one or more segments comprising adsorbentmaterial.

Suitable absorbent materials and suitable adsorbent materials are knownin the art and include, but are not limited to, activated carbon, silicagel and zeolites.

Aerosol-generating articles according to the invention may comprise oneor more aerosol modifying agents downstream of the aerosol-formingsubstrate. For example, where included, one or more of the mouthpiece,aerosol-cooling element and transfer element of aerosol-generatingarticles according to the invention may comprise one or more aerosolmodifying agents.

As used herein with reference to the invention, the term“aerosol-modifying agent” is used to describe an agent that, in use,modifies one or more features or properties of an aerosol generated bythe aerosol-forming substrate of the aerosol-generating article.

Suitable aerosol-modifying agents include, but are not limited to,flavourants and chemesthetic agents.

As used herein with reference to the invention, the term “chemestheticagent” is used to describe an agent that, in use, is perceived in theoral or olfactory cavities of a user by means other than, or in additionto, perception via taste receptor or olfactory receptor cells.Perception of chemesthetic agents is typically via a “trigeminalresponse,” either via the trigeminal nerve, glossopharyngeal nerve, thevagus nerve, or some combination of these. Typically, chemestheticagents are perceived as hot, spicy, cooling, or soothing sensations.

Aerosol-generating articles according to the invention may comprise oneor more aerosol modifying agents that are both a flavourant and achemesthetic agent downstream of the aerosol-forming substrate. Forexample, where included, one or more of the mouthpiece, transfer elementand aerosol-cooling element of aerosol-generating articles according tothe invention may comprise menthol or another flavourant that provides acooling chemesthetic effect.

Aerosol-generating articles according to the invention may comprise oneor more heat-conducting elements.

Preferably, the aerosol-generating articles according to the inventioncomprise a heat-conducting element around at least a portion of theaerosol-forming substrate. The heat-conducting element mayadvantageously transfer heat to the periphery of the aerosol-formingsubstrate by conduction.

More preferably, aerosol-generating articles according to the inventioncomprise a heat-conducting element around and in contact with at least aportion of the aerosol-forming substrate. This may advantageouslyfacilitate conductive heat transfer to the periphery of theaerosol-forming substrate.

The heat-conducting element may be around the entire length of theaerosol-forming substrate. That is, the heat-conducting element mayoverlie the entire length of the aerosol-forming substrate.

Preferably, the heat-conducting element is not around a rear portion ofthe aerosol-forming substrate. That is, the aerosol-forming substrateadvantageously extends longitudinally beyond the heat-conducting elementin a downstream direction.

Preferably, the aerosol-forming substrate extends longitudinally atleast about 3 millimetres beyond the heat-conducting element in adownstream direction.

Preferably, aerosol-generating articles according to the inventioncomprise a heat-conducting element around at least a portion of thereinforced heat source and around at least a portion of theaerosol-forming substrate.

More preferably, aerosol-generating articles according to the inventioncomprise a heat-conducting element around at least a rear portion of thereinforced heat source and around at least a front portion of theaerosol-forming substrate.

Most preferably, aerosol-generating articles according to the inventioncomprise a heat-conducting element around and in contact with at least arear portion of the reinforced heat source and around and in contactwith at least a front portion of the aerosol-forming substrate.

The heat-conducting element may provide a thermal link between thereinforced heat source and the aerosol-forming substrate. This mayadvantageously help to facilitate adequate heat transfer from thecombustible heat source to the aerosol-forming substrate to produce anacceptable aerosol.

Preferably, the rear portion of the reinforced heat source in contactwith the heat-conducting element is between about 2 millimetres andabout 8 millimetres in length.

More preferably, the rear portion of the reinforced heat source incontact with the heat-conducting element is between about 3 millimetresand about 5 millimetres in length.

Preferably, the heat-conducting element is non-combustible.

The heat conducting element may be oxygen restricting. In other words,the heat-conducting element may inhibit or resist the passage of oxygenthrough the heat-conducting element.

The heat-conducting element may be formed from any suitable thermallyconductive material or combination of materials.

Preferably, the heat-conducting element comprises one or moreheat-conductive materials having a bulk thermal conductivity of betweenabout 10 W per metre Kelvin (W/(m·K)) and about 500 W per metre Kelvin(W/(m·K)), more preferably between about 15 W per metre Kelvin (W/(m·K))and about 400 W per metre Kelvin (W/(m·K)), at 23 degrees Celsius and arelative humidity of 50 percent as measured using the modified transientplane source (MTPS) method.

Advantageously, the heat-conducting elements comprises one or moremetals, one or more alloys or a combination of one or more metals andone or more alloys.

Suitable thermally conductive materials are known in the art andinclude, but are not limited to: metal foils, such as, for example,aluminium foil, iron foil and copper foil; and alloy foils, such as, forexample, steel foil.

Advantageously, the heat-conducting element comprises aluminium foil.

Aerosol-generating articles according to the invention may comprise anon-combustible substantially air impermeable barrier between a rear endface of the reinforced heat source and the aerosol-forming substrate.

Inclusion of a non-combustible substantially air impermeable barrierbetween a rear end face of the reinforced heat source and theaerosol-forming substrate may advantageously limit the temperature towhich the aerosol-forming substrate is exposed during ignition andcombustion of the combustible heat source. This may help to avoid orreduce thermal degradation or combustion of the aerosol-formingsubstrate during use of the aerosol-generating article.

Inclusion of a non-combustible substantially air impermeable barrierbetween the rear end face of the reinforced heat source and theaerosol-forming substrate may advantageously substantially prevent orinhibit migration of components of the aerosol-forming substrate to thecombustible heat source during storage and use of the aerosol-generatingarticle.

The barrier may abut one or both of the rear end face of the reinforcedheat source and the aerosol-forming substrate. Alternatively, thebarrier may be longitudinally spaced apart from one or both of the rearend face of the reinforced heat source and the aerosol-formingsubstrate.

Where the combustible heat source does not completely surround thenon-combustible support, the non-combustible support embedded in thecombustible heat source may contact the barrier.

Advantageously, the barrier is adhered or otherwise affixed to the rearend face of the reinforced heat source.

Suitable methods for adhering or affixing a barrier to the rear end faceof the reinforced heat source are known in the art and include, but arenot limited to: spray-coating; vapour deposition; dipping; materialtransfer (for example, brushing or gluing); electrostatic deposition;

pressing; or any combination thereof.

The barrier between the rear end face of the reinforced heat source andthe aerosol-forming substrate may have a low thermal conductivity or ahigh thermal conductivity. For example, the barrier may be formed frommaterial having a bulk thermal conductivity of between about 0.1 W permetre Kelvin (W/(m·K)) and about 200 W per metre Kelvin (W/(m·K)), at 23degrees Celsius and a relative humidity of 50 percent as measured usingthe modified transient plane source (MTPS) method.

The thickness of the barrier between the rear end face of the reinforcedheat source and the aerosol-forming substrate may be selected to achievegood performance. For example, the barrier may have a thickness ofbetween about 10 micrometres and about 500 micrometres.

The barrier between the rear end face of the reinforced heat source andthe aerosol-forming substrate may be formed from one or more suitablematerials that are substantially thermally stable and non-combustible attemperatures achieved by the combustible heat source during ignition andcombustion thereof. Suitable materials are known in the art and include,but are not limited to: clays such as, for example, bentonite andkaolinite; glasses; minerals; ceramic materials; resins; metals; or anycombination thereof.

Preferably, the barrier comprises aluminium foil.

A barrier of aluminium foil may be applied to the rear end face of thereinforced heat source by gluing or pressing it to the reinforced heatsource. The barrier may be cut or otherwise machined so that thealuminium foil covers and adheres to at least substantially the entirerear end face of the reinforced heat source. Advantageously, thealuminium foil covers and adheres to the entire rear end face of thereinforced heat source.

Aerosol-generating articles according to the invention may have anydesired length.

Preferably, aerosol-generating articles according to the invention mayhave a length of between about 65 millimetres and about 100 millimetres.

Aerosol-generating articles according to the invention may have anydesired width.

Preferably, aerosol-generating articles according to the invention mayhave a width of between about 5 millimetres and about 12 millimetres.

Aerosol-generating articles according to the invention may be assembledusing known methods and machinery.

For the avoidance of doubt, where applicable, features described abovein relation to reinforced heat sources according to the invention mayalso be applied to aerosol-generating articles according to theinvention and vice versa.

The invention will be further described, by way of example only, withreference to the accompanying drawings in which:

FIG. 1 shows a schematic longitudinal cross-section of anaerosol-generating article according to the invention;

FIG. 2 shows a schematic transverse cross-section along the line A-A ofthe reinforced heat source of the aerosol-generating article shown inFIG. 1 ;

FIGS. 3 (a), (b) and (c) show schematic transverse cross-sections ofother reinforced heat sources according to the invention;

FIG. 4 (a) shows a schematic longitudinal cross-section of a furtherreinforced heat source according to the invention; and

FIG. 4 (b) shows a schematic transverse cross-section along the line A-Aof the reinforced heat source shown in FIG. 4 (a).

The aerosol-generating article 2 according to the embodiment of theinvention shown in FIG. 1 comprises a reinforced heat source 4 accordingto the invention and an aerosol-forming substrate 10 downstream of thereinforced heat source 4. The reinforced heat source 4 has a front endface 6 and an opposed rear end face 8 and is located at the distal endof the aerosol-generating article 2. The aerosol-generating article 2further comprises a transfer element 12, an aerosol-cooling element 14,a spacer element 16 and a mouthpiece 18. The reinforced heat source 4,aerosol-forming substrate 10, transfer element 12, aerosol-coolingelement 14, spacer element 16 and mouthpiece 18 are arranged in abuttingcoaxial alignment. As shown in FIG. 1 , the aerosol-forming substrate10, transfer element 12, aerosol-cooling element 14, spacer element 16and mouthpiece 18 and a rear portion of the reinforced heat source 4 arewrapped in an outer wrapper 20 of sheet material such as, for example,cigarette paper, metallised paper, or a metal foil-paper laminate.

As shown in FIG. 1 , a non-combustible substantially air impermeablebarrier 22 in the form of a disc of aluminium foil is provided betweenthe rear end face 8 of the reinforced heat source 4 and theaerosol-forming substrate 10. The barrier 22 is applied to the rear endface 8 of the reinforced heat source 4 by pressing the disc of aluminiumfoil onto the rear end face 8 of the reinforced heat source 4 and abutsthe rear end face 8 of the reinforced heat source 4 and theaerosol-forming substrate 10.

The aerosol-forming substrate 10 is located immediately downstream ofthe barrier 22 applied to the rear end face 8 of the reinforced heatsource 4. The aerosol-forming substrate 10 comprises a gathered crimpedsheet of homogenised tobacco material 24 and a wrapper 26 around and indirect contact with the gathered crimped sheet of homogenised tobaccomaterial 24. The gathered crimped sheet of homogenised tobacco material24 comprises an aerosol former such as, for example, glycerine.

The transfer element 12 is located immediately downstream of theaerosol-forming substrate 10 and comprises a cylindrical open-endedhollow cellulose acetate or cardboard tube 28.

The aerosol-cooling element 14 is located immediately downstream of thetransfer element 12 and comprises a gathered sheet of biodegradablepolymeric material such as, for example, polylactic acid.

The spacer element 16 is located immediately downstream of theaerosol-cooling element 14 and comprises a cylindrical open-ended hollowpaper or cardboard tube.

In other embodiments of the invention (not shown), the aerosol-coolingelement 14 and the spacer element 16 may be replaced by an additionaltransfer element comprising a cylindrical open-ended hollow celluloseacetate or cardboard tube.

The mouthpiece 18 is located immediately downstream of the spacerelement 16. As shown in FIG. 1 , the mouthpiece 18 is located at theproximal end of the aerosol-generating article 2 and comprises acylindrical plug of filtration material 30 such as, for example,cellulose acetate tow of very low filtration efficiency, wrapped infilter plug wrap 32.

The aerosol-generating article may further comprise a band of tippingpaper (not shown) circumscribing a downstream end portion of the outerwrapper 20.

As shown in FIG. 1 , the aerosol-generating article 2 further comprisesa heat-conducting element 34 formed from a thermally conductive materialsuch as, for example, aluminium foil around and in contact with a rearportion 4 b of the reinforced heat source 4 and a front portion 10 a ofthe aerosol-forming substrate 10.

In the aerosol-generating article 2 shown in FIG. 1 , theaerosol-forming substrate 10 extends downstream beyond theheat-conducting element 34. That is, the heat-conducting element 34 isnot around and in contact with a rear portion of the aerosol-formingsubstrate 10. However, it will be appreciated that in other embodimentsof the invention (not shown), the heat-conducting element 34 may bearound and in contact with the entire length of the aerosol-formingsubstrate 10. It will also be appreciated that in other embodiments ofthe invention (not shown), one or more additional heat-conductingelements may be provided that overlie the heat-conducting element 34.

The aerosol-generating article 2 according to the embodiment of theinvention shown in FIG. 1 comprises one or more air inlets 36 around theperiphery of the aerosol-forming substrate 10. As shown in FIG. 1 , acircumferential arrangement of air inlets 36 is provided in the wrapper26 of the aerosol-forming substrate 10 and the overlying outer wrapper20 to admit cool air (shown by dotted arrows in FIG. 1 ) into theaerosol-forming substrate 10.

As shown in FIGS. 1 and 2 , the reinforced heat source 4 comprises ablind combustible heat source 38 and a non-combustible support 40embedded in the combustible heat source 38.

The combustible heat source 38 is a cylindrical carbonaceous heat sourcecomprising carbon, an oxidizing agent such as, for example, an alkalineearth metal peroxide, and a binding agent. As shown in FIG. 1 , thecombustible heat source 38 completely surrounds the non-combustiblesupport 40.

The non-combustible support 40 comprises a single elongate rod 42 formedfrom a metal or alloy such as, for example, chromium, iron, nickel,steel, or stainless steel. As shown in FIGS. 1 and 2 , the singleelongate rod 42 extends along the central longitudinal axis of thecombustible heat source 38.

In use, a user ignites the combustible heat source 38. The oxidizingagent in the combustible heat source 38 promotes ignition and sustainedcombustion of the combustible heat source 38 through the release ofoxygen. Once the combustible heat source 38 is ignited the user draws onthe mouthpiece 18 of the aerosol-generating article 2. When a user drawson the mouthpiece 18, cool air (shown by dotted arrows in FIG. 1 ) isdrawn into the aerosol-forming substrate 10 of the aerosol-generatingarticle 2 through the air inlets 36.

The periphery of the front portion 10 a of the aerosol-forming substrate10 is heated by conduction through the rear end face 8 of the reinforcedheat source 4 and the barrier 22 and through the heat-conducting element34.

The heating of the aerosol-forming substrate 10 by conduction releasesaerosol former and other volatile and semi-volatile compounds from thegathered crimped sheet of homogenised tobacco material 24. The compoundsreleased from the aerosol-forming substrate 10 form an aerosol that isentrained in the air drawn into the aerosol-forming substrate 10 of theaerosol-generating article 2 through the air inlets 36 as it flowsthrough the aerosol-forming substrate 10. The drawn air and entrainedaerosol (shown by dashed arrows in FIG. 1 ) pass downstream through theinterior of the cylindrical open-ended hollow cellulose acetate tube 28of the transfer element 12, the aerosol-cooling element 14 and thespacer element 16, where they cool and condense. The cooled drawn airand entrained aerosol pass downstream through the mouthpiece 18 and aredelivered to the user through the proximal end of the aerosol-generatingarticle 2. The non-combustible substantially air impermeable barrier 22on the rear end face 8 of the combustible carbonaceous heat source 4isolates the combustible heat source 4 from air drawn through theaerosol-generating article 2 such that, in use, air drawn through theaerosol-generating article 2 does not come into direct contact with thecombustible heat source 4.

The non-combustible support 40 embedded in the combustible heat source38 reinforces the combustible heat source 38 and advantageously preventsor reduces breakage of the combustible heat source 38 during use.

FIGS. 3 (a), (b) and (c) show schematic transverse cross-sections ofother reinforced heat sources 4 according to the invention. Thereinforced heat sources 4 shown in FIGS. 3 (a), (b) and (c) eachcomprising a combustible heat source 38 and a non-combustible support 40embedded in the combustible heat source 38.

In each of the embodiments shown in FIGS. 3 (a), (b) and (c), thenon-combustible support 40 comprises a plurality of spaced-apartelongate rods 42 formed from a metal or alloy such as, for example,chromium, iron, nickel, steel, or stainless steel. The plurality ofspaced-apart elongate rods 42 extend along the longitudinal axis of thecombustible heat source 38.

FIGS. 4 (a) and (b) show schematic longitudinal and transversecross-sections of a further reinforced heat source according to theinvention. The reinforced heat source 4 shown in FIGS. 4 (a) and (b)comprises a combustible heat source 38 and a non-combustible support 40embedded in the combustible heat source 38.

The non-combustible support 40 comprises a cylindrical open-ended hollowtube 44 formed from a mesh. The mesh may be formed from a metal or alloysuch as, for example, chromium, iron, nickel, steel, or stainless steel.The cylindrical open-ended hollow tube 44 extends along the longitudinalaxis of the combustible heat source 38.

In the reinforced heat sources 4 shown in FIGS. 1, 2, 3 (a), (b) and (c)and 4 (a) and (b) the non-combustible support 40 does not protrudeoutwardly from the combustible heat source 38 and the combustible heatsource 38 completely surrounds the non-combustible support 40. However,it will be appreciated that in other embodiments of the invention (notshown), the non-combustible support may protrude outwardly from thecombustible heat source by a distance of up to 0.1 L, where L is thelength of the combustible heat source.

Reinforced heat sources according to the invention comprising acombustible heat source comprising carbon, calcium peroxide and abinding agent and a non-combustible support comprising a single elongaterod formed from stainless steel are produced having the constructionshown in FIGS. 1 and 2 . Four aerosol-generating articles according tothe invention comprising the reinforced heat sources are produced havingthe construction shown in FIG. 1 .

Comparative heat sources not according to the invention are producedcomprising a combustible heat source having the same composition anddimensions as the combustible heat source of the reinforced heat sourcesaccording to the invention. The comparative heat sources do not comprisea non-combustible support. Four comparative aerosol-generating articlesnot according to the invention comprising the comparative heat sourcesare produced having the same construction as the aerosol-generatingarticles according to the invention.

The reinforced heat sources of the four aerosol-generating articlesaccording to the invention and the comparative heat sources of the fourcomparative aerosol-generating articles not according to the inventionare ignited using a conventional yellow flame lighter.

No ‘fall-off’ or ‘drop-off’ of the reinforced heat sources of the fouraerosol-generating articles according to the invention occurs duringignition or combustion of the reinforced heat sources.

By contrast, ‘fall-off’ or ‘drop-off’ of at least a portion of all ofthe comparative heat sources of the four aerosol-generating articles notaccording to the invention occurs during or shortly after ignition ofthe comparative heat sources.

The results demonstrate that inclusion of a non-combustible supportembedded in the combustible heat source of reinforced heat sourcesaccording to the invention advantageously improves the mechanicalintegrity of reinforced heat sources according to the invention.

The specific embodiments and examples described above illustrate but donot limit the invention. It is to be understood that other embodimentsof the invention may be made and the specific embodiments and examplesdescribed herein are not exhaustive.

1. A reinforced heat source for an aerosol-generating article, thereinforced heat source comprising: a blind combustible heat sourcehaving a length L; and a non-combustible support embedded in thecombustible heat source, wherein the non-combustible support does notprotrude outwardly from the combustible heat source.
 2. A reinforcedheat source according to claim 1 wherein the combustible heat sourcecompletely surrounds the non-combustible support.
 3. A reinforced heatsource according to claim 1 wherein the non-combustible support extendsa distance of between about 0.4 L and about 0.9 L within the combustibleheat source.
 4. A reinforced heat source according to claim 1 whereinthe non-combustible support is formed from one or more materials havinga melting point of greater than or equal to about 1300° C.
 5. Areinforced heat source according to claim 1 wherein the non-combustiblesupport is formed from one or materials selected from the groupconsisting of chromium, iron, nickel and steel.
 6. A reinforced heatsource according to claim 1 wherein the non-combustible supportcomprises one or more non-combustible support elements.
 7. A reinforcedheat source according to claim 6 wherein the one or more non-combustiblesupport elements have a length of between about 0.4 L and about 0.9 L.8. A reinforced heat source according to claim 6 wherein the combustibleheat source has a volume V and the total volume of the one or morenon-combustible support elements is between about 0.00005V and about0.05V.
 9. A reinforced heat source according to claim 1 wherein thenon-combustible support comprises one or more elongate rods.
 10. Areinforced heat source according to claim 9 wherein the combustible heatsource has a diameter D and the one or more elongate rods have adiameter of between about 0.01 D and about 0.3 D.
 11. A reinforced heatsource according to claim 1 wherein the non-combustible support isformed from a mesh.
 12. A reinforced heat source according to claim 1wherein the combustible heat source comprises an oxidizing agent.
 13. Areinforced heat source according to claim 12 wherein the oxidizing agentis an alkaline earth metal peroxide.
 14. A reinforced heat sourceaccording to claim 12 wherein the oxidizing agent is calcium peroxide.15. An aerosol-generating article comprising: a reinforced heat sourceaccording to claim 1; and an aerosol-generating substrate.